I suspect the danger is that if you are using the computer on a train or something it might repeatedly mistake the swaying of the carriage for drops and keep interrupting the disk access by lifting the heads off the disk. Anyway, I probably would have gone for this shock protection if I could... but I guess it is only effective for a computer that is dropped while it is on. The heads are probably parked anyway for a computer that is in standby or off... so the benefit may not be as great as it might first sound.